Among cellular telephone devices as a type of a mobile terminal device that is configured with a first body with an operation unit formed on a top face, and a second body with a display unit formed on a top face, there is a cellular telephone device including a sliding mechanism. By utilizing the sliding mechanism, the cellular telephone device can transition to a state in which the second body covers the operation unit formed on the top face of the first body, by mutually superimposing the first body and the second body such that the display unit is exposed to the outside (hereinafter referred to as a slid-down state), and a state in which the operation unit formed on the top face of the first body is exposed, by sliding the second body in a longitudinal direction relative to the first body (hereinafter referred to as a slid-up state).
By sliding the first body and the second body, a cellular telephone device including such a sliding mechanism transitions to the slid-up state in which the display unit and the operation unit are exposed to the outside, and as a result, it is possible to achieve convenience that key operations can be performed while visually confirming the display screen. Furthermore, the cellular telephone device in the slid-down state has an external appearance that only the display of the first body is exposed to the outside, and as a result, it is possible to achieve space-saving. In addition, if the display is configured with a touch sensor, and/or if a simplified operation unit is formed on the top face of the second body, the cellular telephone device in the slid-down state can also secure operability while achieving space-saving.
For a cellular telephone device including such a sliding mechanism, a method has been proposed, in which a circuit board and a conductor in the bodies are used as antennas (see Patent Document 1). FIGS. 10A, 10B, 11A and 11B are cross-sectional views schematically showing an internal structure of a portable wireless device 200. Moreover, a first body 201 includes an operation unit 202, a circuit board 203, and an antenna 204. A second body 301 includes an operation unit 302, a display 303, and a circuit board 304.
According to a first embodiment of Patent Document 1, in the slid-down state (FIG. 10A), the portable wireless device 200 as an example of a mobile terminal device is configured such that a connection part 204a electrically connected to the antenna 204 is not superimposed, i.e. not coupled at high frequency, with the circuit board 304 of the second body 301 in a thickness direction. As a result, satisfactory antenna characteristics can be achieved in the portable wireless device 200 in the slid-down state.
In addition, the portable wireless device 200 in the slid-up state (FIG. 10B) is configured to supply power to the circuit board 304 of the second body 301 via the connection part 204a that is electrically connected to the antenna 204, so that the circuit board 304 is utilized as an antenna element. As a result, satisfactory antenna characteristics can be achieved in the portable wireless device 200 in the slid-up state. A virtual line A in FIG. 10B schematically shows an aspect in which a high-frequency current is supplied from the first body 201 side to the second body 301 side by connecting the connection part 204a and the circuit board 304.
Furthermore, according to a second embodiment of Patent Document 1, although an outline thereof is substantially similar to that of the first embodiment, the portable wireless device 200 in the slid-up state (FIG. 11A) is configured such that the circuit board 304 is utilized as an antenna element by capacitively coupling the antenna 204 and the circuit board 304 of the second body 301. More specifically, in the portable wireless device 200 in the slid-up state, the antenna 204 and the circuit board 304 of the second body 301 face each other at a predetermined interval to be capacitively coupled with each other. As a result, satisfactory antenna characteristics can be achieved in the portable wireless device 200 in the slid-up state. A virtual line B in FIG. 11A schematically shows an aspect in which a high-frequency current is supplied from the first body 201 side to the second body 301 side by capacitively coupling the antenna 204 and the circuit board 304.
Moreover, similarly to FIG. 10A, the portable wireless device 200 in the slid-down state (FIG. 11B) is configured such that the antenna 204 and the circuit board 304 of the second body 301 do not face each other, and are not capacitively coupled with each other. As a result, satisfactory antenna characteristics can be achieved in the portable wireless device 200 in the slid-down state.
Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2006-67361